Determining Maximum Allowable Current of an RBS Using a Directed Graph Model and Greedy Algorithm

Abstract

Reconfigurable battery systems (RBSs) provide a promising alternative to traditional battery systems due to their flexible and dynamically changeable topological structures that can be adapted to different battery charging and discharging strategies. A critical system parameter known as the maximum allowable current (MAC) is pivotal to RBS operation. This parameter is instrumental in maintaining the current of each individual battery within a safe range and serves as a guiding indicator for the system’s reconfiguration, ensuring its safety and reliability. This paper proposes a method for calculating the MAC of an arbitrary RBS using a greedy algorithm in conjunction with a directed graph model of the RBS. Using the shortest path of the battery, the greedy algorithm transforms the exhaustion of the switch states in the brute-force algorithm or variable search without utilizing structures in the heuristic algorithms in the combination of the shortest paths. The directed graph model, based on an equivalent circuit, provides a specific method for calculating the MAC of a given structure. The proposed method is validated using 2 previously published RBS structures and an additional one with a more complex structure. The results are the same as those from the brute-force algorithm, but the proposed method substantially improves the computational efficiency, being theoretically Ns2Ns − Nblog10Nb times faster than the brute-force algorithm for an RBS with Nb batteries and Ns switches. Another advantage of the proposed method is its ability to calculate the MAC of RBSs with arbitrary structures and variable batteries, even in scenarios with random isolated batteries.